/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Selection/StoredMeshSelectionUtil.h
This is basically just identifying the group edge with a specific component edge, but using vids instead of an edge id makes it a bit easier to apply a compact mapping if the mesh was compacted, and helps the representative survive translation to/from a mesh description in cases of compaction.
namespace UE { namespace Geometry { [FIndex2i](API\Runtime\GeometryCore\FIndex2i) UE::Geometry::GetGroupEdgeRepresentativeVerts ( const [FGroupTopology](API\Plugins\DynamicMesh\FGroupTopology) & TopologyIn, int GroupEdgeID, const [FCompactMaps](API\Runtime\GeometryCore\Util\FCompactMaps) & CompactMaps ) } }